Conventionally, in the field of the semiconductor integrated circuit device etc., various techniques to form a thin film on a substrate with a trench or via hole having an aspect ratio of 1 or more are proposed.
For example, the technique is proposed that prevents the occurrence of voids by forming a barrier film of titanium nitride on the sidewall part and bottom of a trench etc. by reactive ionization sputtering when filling in a trench or via hole having an aspect ratio of 1 or more by reflow (refer to Patent Document 1).
Further, the method of manufacturing an insulating film by ECR plasma CVD is proposed, which enables the reforming of plasma in the vicinity of a substrate, the homogenization of a horizontal film and a vertical film in the step part, and the shape control of the section of the vertical film (refer to Patent Document 2). This method of manufacturing an insulating film is a method of forming a film by alternately repeating the film formation step and sputter step and the magnitude of RF bias is changed between both steps and an etching gas is added in the sputter step.
Furthermore, the method of achieving conformal step coverage on a substrate by PVD is proposed (refer to Patent Document 3). In this method, a signal to be supplied to a target is switched to another alternately at the part of negative voltage and the part of zero voltage during the sputter process and the film deposited on the bottom in the sputter step is redistributed from the bottom to the sidewall in the inverse sputter step. According to this method, it is possible to achieve conformal coverage on the sidewall and bottom of a contact or via having an aspect ratio of 5 or more.
Then, along with high integration of a semiconductor, a technique to form a film in a narrower hole or trench with excellent step coverage is required. For example, the method of forming a silicon dioxide base insulating film in a fine hole or trench having a high aspect ratio with excellent step coverage at low temperature using ECR-plasma CVD is proposed (refer to Patent Document 4).    [Patent Document 1] Japanese Unexamined Patent Application Publication No. 1997-162293    [Patent Document 2] Japanese Unexamined Patent Application Publication No. 1994-252065    [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2001-303247    [Patent Document 4] Japanese Unexamined Patent Application Publication No. 1994-168895